The field of the invention is drywall finishing tools.
Considerable resources have been invested over the years to develop methods and devices for finishing joints. The term xe2x80x9cjointxe2x80x9d, as sometimes used herein, is used in the context of two surfaces which are directly in contact with each other, or which are connected by way of a joining surface. In either case the term joint is used to refer to portions of the two surfaces near where they are joined as well as any joining surface. xe2x80x9cFinishing jointsxe2x80x9d, as sometimes used herein, refers broadly to the process of adding a finishing compound, defined as any viscous substance, so as to form a joint or to modify a previously formed joint. If finishing compound is added to form a joint, the finishing compound is spread onto portions of two surfaces and the substance itself becomes the joining surface. If used to modify the joint, finishing compound is spread onto the joint so as to change some characteristic such as the appearance or durability of the joint.
The term, xe2x80x9cjoint anglexe2x80x9d may be used sometimes hereinafter to describe the angle which is formed by the two joined surfaces, which includes any joining surface and into which the finishing compound is to be spread or applied.
A common example of joint finishing is the application of drywall compound to the corner of a room, the corner formed by placing two sheets of drywall in contact with each other so as to form a 90 degree angle. Any gaps between the sheets are often covered with finishing (xe2x80x9cdrywallxe2x80x9d) tape. Once the joint is formed from the drywall sheets and tape, drywall compound is spread onto the joint. Another example of joint finishing is the spreading of calking into the space between two tiles so that the calking forms a joining surface between the tiles.
Tools to aid in the dispensing and spreading of finishing compounds are known. As an example, U.S. Pat. No. 4,767,297 (the ""297 patent) to Mower and Cezana (Aug. 30, 1988) describes a corner finishing tool having means to contain a supply of mastic, and generally perpendicular means for defining a corner. The tool of ""297, however, will not work if applied to a joint having a joint angle which is significantly greater than 90 degrees. (90 degree joints are sometimes hereinafter referred to as xe2x80x9cperpendicular jointsxe2x80x9d.) Additionally, the tool always forms xe2x80x9csquared offxe2x80x9d joint rather than a xe2x80x9croundedxe2x80x9d joint. (The term xe2x80x9cnon-perpendicularxe2x80x9d joints is sometimes hereinafter used to refer to all joints which are not perpendicular, including xe2x80x9croundedxe2x80x9d joints.) Squared off joints have the disadvantage that they form a visual line along the joint which makes it easy to visually determine how straight the joint is. As a result, extra time and effort is often spent trying to xe2x80x9cstraightenxe2x80x9d the visual line.
The visual line problem can be eliminated by forming a xe2x80x9croundedxe2x80x9d joint rather than a xe2x80x9csquared offxe2x80x9d joint, largely because a xe2x80x9croundedxe2x80x9d joint eliminates the visual. Tools, such as those described in U.S. Pat. No. 4,919,604 to Wilson (Apr. 24, 1990) and U.S. Pat. No. 4,784,598 to Kranz et al (Nov. 15, 1988), can be used to product xe2x80x9croundedxe2x80x9d joints. Another advantage of using a tool suitable to form xe2x80x9croundedxe2x80x9d corners is that it is more likely to work in corners having a joint angle which is significantly greater than 90 degrees.
Previously known tools suitable for forming xe2x80x9croundedxe2x80x9d corners do, however, suffer from a severe limitation in that they are not suitable for use with a finishing compound dispenser. Thus, the application and spreading of finishing compound cannot be done in a single pass. Instead, finishing compound must first be applied. Once that is done, one must switch between the application tool and the finishing tool, and then make a second pass along the joint. A related problem is that it is difficult to judge how much finishing compound to use. If all the finishing compound is applied before spreading begins, errors in the amount of compound applied become troublesome. If too little compound is applied, the process of application and spreading must be repeated. If too much compound is applied, the excess compound tends to get pushed into xe2x80x9cpilesxe2x80x9d which require extra effort to remove. However, if the compound is applied on a continuous basis and is immediately being spread the problem is essentially solved because it is possible to adjust the amount of compound being applied before any lack or surplus becomes problematic.
Joints having joint angle which vary significantly from 90 degrees tend to be troublesome. The xe2x80x9csquared offxe2x80x9d tools often will not work if the joint angle is much greater or less than 90 degrees. Even if a xe2x80x9csquared offxe2x80x9d tool was hinged to allow it to deal with such angles, it would still have the problem of creating a visual line, and the greater the joint angle, the more difficult it is to keep that visual line straight. The xe2x80x9croundedxe2x80x9d tools will often work with joint angles which are greater than 90 degrees, but, in addition to being incapable of both dispensing and spreading, are not suited for joint angles which are greater than 180 degrees.
Thus, there is a continuing need to improve tools and methods for finishing joints.
The present invention is directed to methods and devices for finishing non-perpendicular joints, including a corner finishing tool comprising a hard planar spreading member, a receiver portion, and a tensioning assembly. The spreading member has upper and lower surfaces, each surface having front, rear, left and right edges, wherein the spreading member can be flexed so as to move from an un-flexed state to a flexed state by moving the left and right edges upward and towards each other. The receiver portion is sized and dimensioned to receive a finishing compound dispenser and includes a through hole extending between the upper and lower surfaces of the spreading member. The tensioning assembly provide the capability of increasing and decreasing the amount of force required to flex the left and right edges towards each other.
Various objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of preferred embodiments of the invention, along with the accompanying drawings in which like numerals represent like components.